The new regulator comes as an assembled unit with motor, you can not buy them separately. Cost is in the neighborhood of $100 per side.
To change them out, first take the door panel off of course and remove the water proof sheeting.
There will be a black plastic plug right below the window motor, pry it out and there is an electrical connector behind it for the motor, unplug it.
Slide the glass up by hand (if it binds, you can cut the cable) and remove the two 10mm bolts on the bottom edge of the glass; this separates the glass from the regulator.
You can use tape or suctions cups on strings to hold the glass in the up position, or gently slide it back down... note that if you leave it down it makes things much tighter and you risk damaging window tint if you have any.
Locate the three 10mm bolts around the window motor (just above where you unplugged it) and remove them.
Locate the three 10mm bolts holding the regulator to the door frame; there are two at the top center of the track and one at the bottom center of the track, remove them and slide the track and motor assembly rearward out of the door. Note that the motor has a plastic square peg that it hangs from in the door frame.
Reassemble in reverse order, make sure the bolts go back in their original locations... the glass bolts are shorter than the other 6; the motor bolts will typically have a philips slot cut into the head, whereas the track bolts do not.
Here is an illustration designating where the bolts are located in case you have difficulty locating them:
